500. Keyboard Row

Given a List of words, return the words that can be typed using letters of alphabet on only one row's of American keyboard like the image below.

 

 

Example 1:

Input: ["Hello", "Alaska", "Dad", "Peace"]
Output: ["Alaska", "Dad"]

 

Note:

1. You may use one character in the keyboard more than once.
2. You may assume the input string will only contain letters of alphabet.

 

 

Subscribe to see which companies asked this question.

 

 

#include<iostream>
#include<string>
#include<vector>
#include<map>
#include <algorithm>
using namespace std;
class Solution {
public:
void findWords(vector<string>& words) {
vector<string> strs ={ "QWERTYUIOP", "ASDFGHJKL", "ZXCVBNM" };
map<char, int> map;
for (int i = 0; i<strs.size(); i++){
for (char c : strs[i]){
map.insert(pair<char, int>(c, i));//put <char, rowIndex> pair into the map
}
}
vector<string> res;
vector<string> dst(words.size());

for (int i = 0; i < words.size(); i++)
transform(words[i].begin(), words[i].end(), back_inserter(dst[i]), ::toupper);

for (int i = 0; i<dst.size(); i++){
if (dst[i] == "")
continue;
int index = map[dst[i][0]];
for (int j = 0;j<dst[i].size();j++){
if (map[dst[i][j]] != index){
index = -1; //don't need a boolean flag.
break;
}
}
if (index != -1) res.push_back(words[i]);//if index != -1, this is a valid string
}
for (auto w : res){
cout << w << " ";
cout << endl;
}

}
};
int main()
{
vector<string> word = { "Hello", "Alaska", "Dad", "Peace" };
Solution s;
s.findWords(word);
system("pause");
return 0;
}